1. Field of Invention
The invention relates to an ink cartridge for use with a printing apparatus capable of performing printing via a liquid ink.
2. Description of Related Art
In an ink jet print head for use with a printing apparatus, such as an ink jet printer, a curved surface (meniscus) of ink liquid needs to be formed in ink nozzle openings of the ink jet print heads for printing to be performed properly. For the meniscus to be formed for proper printing, appropriate negative pressures need to be applied and maintained while ink is supplied.
A compact and lightweight ink cartridge exists that is used for a portable printer and the like, having a structure such that ink contained in a flexible bag of an ink pack is supplied to a print head from the ink pack through an ink extracting needle inserted into the ink pack. The ink cartridge having the flexible ink pack may maintain negative pressures therein due to the rigidity and strength of the bag.
However, to certainly apply and maintain the appropriate negative pressures for the above-described reasons, an upper supporting spring 151 is used in the following manner. As shown in FIG. 13, a thin sheet-like bag of an ink pack 109a is horizontally provided. The lower surface of the ink pack 109a is adhered to the lower surface of an ink pack housing 192 of an cartridge body 191, which has a generally box shape. To the upper surface of the ink pack 109a, an upper supporting spring 151 whose one end is secured by the cartridge body 191, is adhered. Using only one upper supporting spring 151, the ink pack 109a is urged/pulled so as to expand upwardly. In such ink cartridge, negative pressures can certainly be applied to the ink by the upper supporting spring 151.
In the ink cartridge employing above-described structure, the ink extracting needle 110 for extracting ink needs to be inserted into the ink pack 109a. For the ink extracting needle 110 to be easily inserted, the upper and lower surfaces of the ink pack 109a are fixed to the upper supporting spring 151 or the cartridge body 191. The ink extracting needle 110 is inserted into an insert portion 109c provided in the substantially central portion of the ink pack 109a when it is fixed with the upper and lower surfaces thereof, so that the sharp pointed end of the needle does not interfere with the bag of the ink pack 109a. 
Since the ink cartridge of this invention has two plate springs, they can be disposed according to the shape of the ink pack, and the ink pack can be urged/pulled upwardly and downwardly so as to apply negative pressures thereto. The ink remaining in the ink pack can be reduced and greater amounts of ink can be used from the ink pack urged/pulled by two plate springs than that urged/pulled by one plate spring, if the ink pack contains the same amount of ink. Consequently, the running costs of the printer are cut down and the time during which the printer can continuously be used becomes long.
Furthermore, since the two plate springs are used to urge/pull the ink pack, appropriate negative pressures can be applied to the ink pack in a wider range with respect to the amount of ink usage, than one plate spring used to apply negative pressures, wherein small amounts of urging/pulling forces are applied to the ink pack filled up with the ink and when the ink is used and the volume of the ink decreases, the greater amount of urging/pulling forces are applied as the application point of the urging/pulling forces is changed and the plate spring bends down. Since the appropriate negative pressures can be maintained from the start to the end of the ink usage using two plate springs, meniscuses (curved surfaces) of ink liquid are properly formed in the nozzles of the ink jet print head and poor printing, such as excessive amounts of ink droplets ejected, splattered inks, ink blurred, and no ink ejected will not occur.
In the ink cartridge of the invention, at least one of the pair of plate springs is supported near the ink extracting portion so as to dispose the ink extracting needle therebetween when the ink extracting needle is inserted.
Since the ink cartridge of this invention has two plate springs, they can be disposed according to the shape of the ink pack, especially according to the position of the ink extracting needle, and the ink pack can be urged/pulled upwardly and downwardly as to apply negative pressures thereto. The ink remaining in the ink pack can be reduced and a greater amount of ink can be used from the ink pack urged/pulled by two plate springs than that urged/pulled by one plate spring, if the ink pack contains the same amount of ink. Consequently, the running costs of the printer are cut down and the time during which the printer can continuously be used becomes long.
The at least one of the pair of plate springs has a substantially C- or O-shaped outer portion whose one end is movably supported at the housing and a central portion movably supported with an inner surface of the outer portion at the opposite side of the supporting portion of the outer portion, wherein the central portion is fixed to the ink pack.
Since the substantial length of the plate spring can be extended, the appropriate urging/pulling forces can be applied when the application point of the urging/pulling forces to the ink pack is greatly changed, and appropriate negative pressures can be applied to the ink pack in a wide range with respect to the amount of ink usage. Since the appropriate negative pressures can be maintained from the start to the end of the ink usage, meniscuses (curved surfaces) of ink liquid are properly formed in the nozzles of the ink jet print heads and the poor printing, such as an excessive amount of ink droplets ejected, splattered inks, ink blurred, and no ink ejected will not occur.
The substantially C- or O-shaped outer portion of the at least one of the pair of plate springs whose one end is movably supported at the housing, is supported at the portion opposite to that which the outer portion of the other plate spring is supported at.
Therefore, the two plate springs interact with each other to maintain appropriate negative pressures and to effectively reduce the ink remaining in the ink pack.
In the ink cartridge of this invention, the pair of plate springs are uniformly formed.
Therefore, it becomes possible to effectively produce one piece of plate spring.
Further, the housing contains a plurality of the ink packs.
Therefore, it becomes possible to supply a plurality of inks to a printing apparatus that performs printing using a plurality of inks for color printing.
In the ink cartridge of the invention, the ink is supplied to an ink jet print head included in an image forming apparatus.
Therefore, it becomes possible to properly supply the ink to the ink jet print head of the image forming apparatus.
In accordance with the invention, an ink cartridge includes a flexible bag of an ink pack that contains liquid ink, a housing that houses the ink pack, a first urging/pulling device that urges/pulls the bag of the ink pack to apply negative pressures to the liquid ink contained in the ink pack, a second urging/pulling device that applies negative pressures with smaller amounts of force than the first urging/pulling device does, a releasing device that releases the first urging/pulling device therefrom.
Since the releasing device releases the first urging/pulling device therefrom according to the amount of ink in the ink pack, appropriate negative pressures can be maintained with different amounts of urging/pulling forces applied. By adjusting the pressure of the liquid ink to be supplied at negative pressures appropriate for printing, proper meniscuses can be formed, and high-quality printing can be produced.
The releasing device includes an engagement portion fixed to the ink pack and an engagement catch, provided on the first urging/pulling device, to be engaged in the engagement portion, wherein the engagement catch engaged in the engagement portion is released by the positional change of the engagement portion due to the decrease in the amount of ink in the ink pack.
Since the releasing device releases the first urging/pulling device therefrom using the engagement portion that changes its position according to the amount of ink used, urging/pulling forces are adjusted according to the amount of ink used. Therefore, the appropriate urging/pulling forces are applied regardless of the amount of ink used, applying negative pressures appropriate for printing, to the ink.
Further, the releasing device has the engagement portion fixed to an opposite side of the ink pack fixed to the inner wall of the housing with a portion thereof and the engagement catch of a plate spring forming the first urging/pulling device whose one end is fixed to the inner wall of the housing with the predetermined supporting point, wherein the engagement catch is engaged in the engagement portion so as to urge/pull the ink pack to apply negative pressures thereto when more than a predetermined amount of liquid ink are filled in the ink pack, and the engagement portion releases the engagement catch therefrom when the predetermined amount of ink is used from the ink pack by changing its position downwardly from the supporting point of the first urging/pulling device as the ink is used.
Since the walls of the ink pack deform or move when ink is used, when a predetermined amount of ink is used the first urging/pulling device is mechanically released with the use of deformation or movement of the walls of the ink pack. After the first urging/pulling device is released, the second urging/pulling device is employed to apply appropriate urging/pulling forces to the ink pack. Therefore, the appropriate urging/pulling forces are applied regardless of the amount of ink used, applying negative pressures appropriate for printing, to the ink.
The releasing device includes a guide member to guide the positional change of the engagement portion.
Since the guide member guides the engagement portion, and regulates the path of the engagement portion according to the amount of ink used, the distance from the supporting points of the first urging/pulling device to the engagement portion is accurately regulated according to the amount of ink used, and the first urging/pulling device can be released at the right time when the predetermined ink is used.
Furthermore, the releasing device includes the guide member to guide the end of the engagement catch.
Since the engagement catch changes its position with the end of the engagement catch regulated by the guide member, the first urging/pulling device can be released at the right time when the predetermined ink is used.
The second urging/pulling device urges/pulls the ink pack with the elasticity of the ink pack.
Since the second urging/pulling device uses the elasticity of the ink pack, other urging/pulling mechanisms do not have to be provided. Therefore, the compact design of the ink cartridge can be pursued.
The ink pack is urged/pulled with the rigidity and strength on the walls increased by the lamination of a plurality of synthetic resin films.
Since the rigidity and strength of the walls of the ink pack are increased by the lamination of a plurality of synthetic resin films, the appropriate negative pressures can be applied to the ink to be supplied.
The second urging/pulling device urges/pulls the ink pack by a plate spring attached to the ink pack.
Since the plate spring is used to urge/pull the ink pack, the appropriate urging/pulling forces can be applied regardless of the ink pack material by flexibly adjusting the elasticity of the plate spring.
In the ink cartridge of the invention, a plurality of ink packs are provided.
Since a plurality of ink packs are provided, it can accommodate a printing apparatus that performs color printing or that produces various tones of colors.
The housing has an ink extracting portion having a rubber member into which a hollow ink extracting needle is inserted to extract the ink from the ink pack contained in the housing.
Therefore, it becomes possible to extract the ink from the ink pack via the ink extracting needle, and the constriction of the ink pack can be simplified. Furthermore, even if the ink is leaked out of the portion where the ink extracting needle is inserted, the ink extracting portion having the rubber member prevents the ink from leaking out of the ink cartridge, so that the printing apparatus or its users will not be soiled with the ink.
The ink is supplied to an ink jet print head included in an image forming apparatus.
The liquid ink whose pressures are kept at the appropriate negative pressures can be supplied to an ink jet print head which is easily affected especially by the negative pressures of the liquid ink to be supplied. Therefore, the meniscuses can be properly formed, producing the high-quality images.
In the ink cartridge of the invention, the ink is supplied to the ink jet print head via a tube.
Since appropriate negative pressures are applied to the liquid ink despite the pressures attributable to the height differences between the bag of the ink pack and the ink jet print head, the liquid ink whose pressures are kept at the appropriate pressures, can be supplied from the bag of the ink pack to the ink jet print head via the tube. Therefore, high-quality images can be produced.